Current Sensing Load Demand Apparatus and Methods

ABSTRACT

An apparatus supplies AC power to a load. The apparatus includes a set output terminals, a primary circuit, and a load sensing circuit. The primary circuit is electrically coupled to a source of AC power and to the output terminals for selectively providing power at a low voltage at the output terminals or electronically coupling the source of AC power directly to the output terminals. The load sensing circuit coupled to the primary circuit and the source of AC power for determining a resistance associated with the load at initial application of the load and controlling the primary circuit to electronically couple the source of AC power directly to the output terminals if a proper load is detected.

RELATED APPLICATION

This applications claims priority to U.S. Provisional Patent ApplicationSer. No. 60/823,455, filed Aug. 24, 2006, the entire specification ofwhich is hereby expressly incorporated by reference.

FIELD OF THE INVENTION

This description relates generally to electrical receptacles and moreparticularly to a method of load verification of an electrical currentdemand, which ensures such demand does not exceed the operationalparameters of said receptacles.

BACKGROUND

Conventional electrical receptacles used in industrial, commercial andresidential applications deliver electricity to a variety of electricalappliances. The receptacles manufactured today have a hard Lexan plasticenclosure and deliver a hot, neutral and ground to said electricalappliances via a plug which is inserted into three of the six holes in atypical grounded application. Voltage and current travel through the hotconductor to the appliance circuit. If the appliance circuit is switchedon, the voltage and current flow through to the neutral conductorcompleting the circuit. The circuit has an inherent resistanceassociated with the appliance load demand whereby the resistancedetermines the load requirement. If there is no resistance in thecircuit, it is a short between the hot conductor and neutral conductorand if the resistance is infinite then there is an open short on one ofthe conductors. The description set forth in this patent describes insufficient detail a circuit which determines these conditions ofresistance before delivering the voltage and current to the hotconductor of the appliance and it is understood that various electronicdesigns changes could be made without departing from the scope or thespirit of the related art.

Electrical receptacles configured to eliminate arc faults rather thanmerely detect such faults with attendant circuit disconnection; theinvention contemplates low-cost, child-safe electrical receptaclesuseful in residential situations and which can be fitted within theconfines of single gang enclosures. The safety receptacles of theinvention can be used in all use situations including residential,commercial and industrial applications to increase safe use ofelectrical receptacles in residential applications in particular and todecrease industrial liabilities. In essence, the safety receptacles ofthe invention prevent arcing during insertion of a plug into thereceptacle, during residence of the plug in the receptacle and duringremoval of the plug from the receptacle with a substantial load to thereceptacle while determining the load demand does not exceed thereceptacle's electrical specification.

An arc fault circuit interrupter (AFCI) is a circuit breaker designed toprevent fires by detecting non-working electrical arcs and disconnectpower before the arc starts a fire. Advanced electronics inside an AFCIbreaker detect sudden bursts of electrical current in milliseconds, longbefore they would trip a regular overcurrent circuit breaker or fuse.The AFCI should distinguish between a working arc that may occur in thebrushes of a vacuum sweeper, light switch, or other household devicesand a non-working arc that can occur, for instance, in a lamp cord thathas a broken conductor in the cord from overuse. Arc faults in a home isone of the leading causes for household fires.

AFCIs resemble a GFCI/RCD (Ground-Fault CircuitInterrupt/Residual-Current Device) in that they both have a test button,though it is important to distinguish between the two. GFCIs aredesigned to protect against electrical shock, while AFCIs are primarilydesigned to protect against fire

Starting with the 1999 version of the National Electrical Code in theUnited States and the 2002 version of the Canadian Electrical Code inCanada, AFCI are now required in all circuits that feed receptacles inbedrooms of dwelling units. The National Electrical Code is an industryconsensus document adopted by many U.S. municipalities. This requirementof the NEC is typically accomplished by using a kind of circuit-breaker(defined by UL 1699) in the breaker panel that provides combinedarc-fault, ground-fault, and over-current protection. The ground-faultprotection is intended to prevent fire from arcs to ground and works ata higher threshold (30 mA) than the GFCI/RCD (Ground-Fault CircuitInterrupt/Residual-Current Device) implementations protecting againstthe safety hazard of electric shock (which operate at 6 mA). Combineddevices are available which trip at the lower, 6 mA threshold of a trueGFCI/RCD.

Even AFCI's do not, however, provide protection against all of thepossible circuit faults that could ignite a fire. In particular, theyprovide no special protection against so-called “glow faults” where arelatively low-resistance short circuit draws a modest amount of current(within the trip limits of the circuit breaker) but heats the localizedarea of the fault to red heat. Glow faults also can occur where aconnection in series with a load suddenly develops a high resistance;this might be the result of a now-defective switch, socket, plug, orwire connection (series faults are observed with special frequency inaluminum wire junctions). No practical circuit breaker could detecteither such fault as there is no measurable characteristic that anycircuit breaker could employ to distinguish a glow fault from the normaloperation of a branch circuit.

Power outlets or receptacles are designed for power distribution throughout various structures around the world and are designed with ease ofmanufacturing and installation design standards. If a short by aconductor is connected between the Neutral and Hot side of a receptacle,the said receptacle will arc, possibly causing fire or electrocution. Inthe patent Chapman et al; U.S. Pat. No. 6,678,131: Arc-safe electricalreceptacles the use of a “Quench arc circuit” is utilized to reduce thearc between the contact points whereby said contact points are bypassedby aforementioned capacitor based quench arc circuit. Closely examiningthe circuit, one can determine the hot side of the quench arc circuitwould short to ground causing discharge of electrical flow prior tocontact closure.

Electrical receptacle outlets in walls and floors may present shock andelectrical fire hazards to consumers. The U.S. Consumer Product SafetyCommission estimates that 3,900 injuries associated with electricalreceptacle outlets are treated in hospital emergency rooms each year.Approximately a third of these injuries occur when young children insertmetal objects, such as hair pins and keys, into the outlet, resulting inelectric shock or burn injuries to the hand or finger. CPSC alsoestimates that electric receptacles are involved in 5,300 fires annuallywhich claim 40 lives and injured 110 consumers. Outlets with poorinternal contacts or loose wire terminals may become overheated and emitsparks. Even a receptacle with nothing plugged into it may run hot if itis passing current through to other outlets on the same circuit. Toprevent damage to receptacles, appliances should be switched-off beforeunplugging from a receptacle.

The present invention is aimed at one or more of the problems describedabove.

SUMMARY OF THE INVENTION

In one aspect of the present invention, an apparatus for supplying ACpower to a load is provided. The apparatus includes a set outputterminals, a primary circuit, and a load sensing circuit. The primarycircuit is electrically coupled to a source of AC power and to theoutput terminals for selectively providing power at a low voltage at theoutput terminals or electronically coupling the source of AC powerdirectly to the output terminals. The load sensing circuit coupled tothe primary circuit and the source of AC power for determining aresistance associated with the load at initial application of the loadand controlling the primary circuit to electronically couple the sourceof AC power directly to the output terminals if a proper load isdetected.

In a second aspect of the present invention, an apparatus for supplyingAC power to a load is provided. The apparatus includes a primary circuitand a load sensing circuit. The primary circuit is electrically coupledto a source of AC power. The source of AC power has a neutral terminaland a positive terminal. The primary circuit includes a power supply andvoltage regulator circuit, a first switch, and a second switch. Thepower supply and voltage regulator circuit is electrically coupled tothe neutral and positive terminals and supplies power at a low voltage.The first switch is coupled to the power supply and voltage regulatorcircuit, for sensing application of a load and responsively electricallycoupling the power supply and voltage regulator circuit to the load. Thesecond switch is electrically coupled between the first switch and theload and having a first position where the first switch and the load areelectrically coupled and a second position where the source of AC poweris electrically coupled directly to load. The load sensing circuit iscoupled to the power supply and voltage regulator circuit fordetermining a resistance of the load after application of the load andcontrolling the switch to move to the second position if a proper loadis detected.

In a third aspect of the present invention, a receptacle for supplyingAC power to a load is provided. The load has an associated electricalplug. The receptacle includes a set of outlet terminals, an outlet, aprimary circuit, and a load sensing circuit. The outlet receives theelectrical plug associated with the load. The outlet has at least twoassociated electrical connectors electrically coupled to the outletterminals for providing electrical connection to associated prongs ofthe electrical plug. The primary circuit is electrically coupled to asource of AC power and to the output terminals. The source of AC powerhas a neutral terminal and a positive terminal. The primary circuitincludes a power supply and voltage regulator circuit, which iselectrically coupled to the neutral and positive terminals and suppliespower at a low voltage, and first and second switches. The first switchis coupled to the power supply and voltage regulator circuit, forsensing insertion of the electrical plug into the outlet andresponsively electrically coupling the power supply and voltageregulator circuit to the load. The second switch is electrically coupledbetween the first switch and the output terminals and has a firstposition where the first switch and the output terminals areelectrically coupled and a second position where the source of AC poweris electrically coupled directly to the output terminals. The loadsensing circuit is coupled to the power supply and voltage regulatorcircuit for determining a resistance of the load after insertion of theelectrical plug into the outlet and controlling the switch to move tothe second position if a proper load is detected.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an apparatus for providing AC power to aload, according to one aspect of the present invention;

FIG. 2 is a schematic diagram of a plurality of load sensing circuitsprovided for standard plug configurations, according to an embodiment ofthe present invention;

FIG. 3 is a schematic diagram of a singular load sense circuit providedfor single plug configurations, according to an embodiment of thepresent invention;

FIG. 4 is a logic flow chart for load sensing circuit, according to anembodiment of the present invention;

FIG. 5 is an exploded view of an apparatus for providing AC power to aload embodied in a receptacle, according to an embodiment of the presentinvention;

FIG. 6 is a logical flow diagram of input hardware which depictsoperational conditions based on load qualifications, according to anembodiment of the present invention;

FIG. 7 is a schematic of a RCTIME circuit, for use in an apparatus forproviding AC power to a load, according to an embodiment of the presentinvention;

FIG. 8 is a schematic of a five volt neutral sense RCTIME circuitthrough a Double Pole single Throw Relay further comprising of 120 voltswitching circuit and load monitoring schematic diagram, according to anembodiment of the present invention;

FIG. 9 is a logical flow chart of RFID or equivalent identificationcircuit, according to an embodiment of the present invention;

FIG. 10 is an exploded view of an apparatus for providing AC power to aload embodied in a receptacle with three boards, according to anembodiment of the present invention;

FIG. 11 is a downward view of a top board, of the apparatus of FIG. 10,outlining the neutral, hot and ground with a neutral side sensor andmechanical supports;

FIG. 12 is a downward view of the middle board, of the apparatus of FIG.10, outlining the MCU board, relative humidity/temperature board, andthe RFID board along with power switching relays; and,

FIG. 13 shows a downward view of the power supply and the mechanicalsupports of the apparatus of FIG. 10.

DETAILED DESCRIPTION

With reference to the drawings and in operation, the present inventionprovides an apparatus 10 for supplying AC Power to a load 12.

With particular reference to FIG. 1, the apparatus 10 includes a pair ofoutput terminals 14, a primary circuit 16, and a load sensing circuit18. The primary circuit 16 is electrically coupled to a source of ACpower 20 and to the output terminals 14. The primary circuit 16selectively provides power at a low voltage at the output terminals 14or electronically couples the source of AC power 20 directly to theoutput terminals 14. In one aspect of the present invention, the primarycircuit 16 provides power at the low voltage at the application of theload 12.

The load sensing circuit 18 is coupled to the primary circuit 16 and thesource of AC power 10. The load sensing circuit 18 determines aresistance associated with the load 12 at initial application of theload 12 and controls the primary circuit 16 to electronically couple thesource of AC power 20 directly to the output terminals 14 if a properload is detected.

For example, as explained below, the apparatus 10 may be embodied in areceptacle into which an electrical plug of a load, e.g., a vacuum orlight is inserted. A specific load has a certain load characteristicswhich defines the current required or drawn by the load when applied tothe source of AC power. However, during the insertion of the plug intothe receptacle, the load has a different set of characteristics whichmay draw a different current, referred to as the inrush current. If theload is improper, e.g., there is a short circuit, the load or resistanceof the load during the application of the load will be negligible, i.e.,zero or almost zero.

In one aspect of the present invention, the load sensing circuit 18continues to supply power at the low voltage at least during initialload characteristics associated with the application of the load 12.

In another aspect of the present invention, as discussed below, theapparatus 10 supplies no power to the output terminals 14 when no loadis present, supplies power at the low voltage during application of theload, e.g., insertion of an electrical plug, and supplies AC power tothe load if a proper load is detected.

In another aspect of the present invention, the load sensing circuit 18determines a resistance associated with the load 12 after initialapplication of the load 12, if a proper load is not previously detectedand confirms that the load is not proper as a function of the resistanceassociated with the load after initial application of the load. In someinstances, a proper load may appear to the load sensing circuit 18 likean improper load at insertion or application of the load. For example, alamp or lightbulb may appear as a short during insertion or applicationof the load. Therefore, in one embodiment, the load sensing circuit 18may “double-check” to determine if the previously “improper” loadmatches the load characteristics of a proper load at some time afterinitial application.

With particular reference to FIGS. 2, 5, and 10-13, in one embodiment ofthe present invention, the apparatus 10 is embodied in an electricalreceptacle 22 which is adapted to receive electrical plugs correspondingto various loads in a conventional manner. As shown, the electricalreceptacle 22 include first and second outlets 24A, 24B.

With particular reference to FIG. 2, in one embodiment the apparatus 10includes a first primary circuit 16A and a second primary circuit 16B.Incoming hot terminals 26 (which are connected to the source of AC power20) feed into the first and second primary circuits 16A, 16B. The firstprimary circuit 16A utilizes incoming voltage and current to passthrough a power supply 28 (60 mA) where a small amount of current flowthrough a 5 volt voltage regulator 30A (LM317) to allow a safer andlower voltage to pass through the initial load via a first switch 32A(SW1). In the illustrated embodiment,

With particular reference to FIG. 10, in the illustrated embodiment, thefirst switch 32A is located in the neutral side of the female pluginsertion and is mechanically actuated by the insertion of adjoiningmale plug 34.

Returning to FIG. 2, the first primary circuit includes a contactor 36A(which is embodied in a first relay 38A in the illustrated embodiment)and the load sensing circuit 18 include a microcontroller 40. The 5volts leaving the voltage regulator 30A junctions to an input of themicrocontroller 40 input where firmware coding incrementally divides thevoltage into 256 segments (0-255 respectively). As the resistance to the5 volt input increases, the current demand decreases. If there is noresistance then there is a short across the output hot and the outputneutral and the load sensing circuit 18 does not actuate the contactor36 sA. If the resistance is too high for the rating of the plug, theload sensing circuit 18 does not actuate the first contactor 36A.Pending proper resistance detection, the load sensing circuit 18actuates the first contactor 36A, thus directly connecting the outputterminals with the source of AC power 10.

In one embodiment, the apparatus 10 may include an indicator 44electrically connected to both the first and second primary circuits16A, 16B. If first and second scenario occurs, the microcontroller 40can utilize the indicator 42 such as a buzzer 44 or an LED indicator orboth to provide a status signal, i.e., proper or improper load.

The second primary circuit 16B utilizes incoming voltage and current topass through the power supply 28 (60 mA) where a small amount of currentflow through a second 5 volt voltage regulator 30B (LM317) to allow asafer and lower voltage to pass through the initial load via a secondfirst switch (SW2). The 5 volts leaving the second voltage regulator 30Bjunctions to an input of the microcontroller 40 where firmware codingincrementally divides the voltage into 256 segments (0-255respectively). As the resistance to the 5 volt input increases, thecurrent demand decreases. If there is no resistance then there is ashort across the output hot and the output neutral and the load sensingcircuit 18 does not actuate a second contactor 36B (which is embodied ina first relay 38A (R2) in the illustrated embodiment). If the resistanceis too high for the rating of the plug, the load sensing circuit 18 doesnot actuate the second contactor 36B. Pending proper resistancedetection, the load sensing circuit 18 actuates the second contactor36B, thus directly connecting the output terminals with the source of ACpower 10. If first and second scenario occurs, the microcontroller 40can utilize the indicator 42.

In the illustrated embodiment, the apparatus 10 utilizes a singlemicrocontroller 40 for both primary circuits 16A, 16B and a singleindicator 42.

With reference to FIG. 3, in a second embodiment the apparatus 10 isused in a single application, i.e., includes a single set of outputterminals 14. A primary circuit 16 utilizes incoming voltage and currentto pass through a power supply 28 (60 mA) where a small amount ofcurrent flow through a 5 volt voltage regulator 30 (LM317) to allow asafer and lower voltage to pass through the initial load via a firstswitch 32. In one aspect, the first switch 32 is located in the neutralside of the female plug insertion and is mechanically actuated by theinsertion of adjoining male plug. The 5 volts leaving the voltageregulator 30 junctions to an input of a microcontroller 40 wherefirmware coding incrementally divides the voltage into 256 segments(0-255 respectively). As the resistance to the 5 volt input increases,the current demand decreases. If there is no resistance then there is ashort across the output hot and the output neutral terminals 14 and theload sensing circuit 18 does not actuate a contactor 36 (shown as arelay 38 in the illustrated embodiment). If the resistance is too highfor the rating of the plug, the load sensing circuit 18 does not actuatethe contactor 36. Pending proper resistance detection, the load sensingcircuit 18 actuates the contactor 36. If first and second scenariooccurs, the microcontroller 40 can utilize an indicator 42 such as aBuzzer 44 or an LED indicator or both.

FIG. 4 shows a block diagram whereby incoming voltage and current arepassed through a load sensor 46 before a load controller 48 allows saidvoltage and current to pass through to the load 50. If the resistance istoo high, the sensor actuates the indicator which indicates the load isout of range of the operational parameters of the receptacle. If theproper resistance is detected, the load sensor 46 may actuates theindicator buzzer in a pulse indicating the voltage and current will passthrough to the load 52.

With specific reference to FIG. 5, the apparatus 10 may be embodied in atwo outlet 24A, 24B receptacle 22. The load's electrical plug isinserted into the face of the receptacle 22 via plug prongs. A neutralopening 50 allows the prong to make neutral connection to a soft brassconnector 52. Below the connector is a small sensor 54 which is utilizedto detect the presence of the neutral prong whereby five (5) volts ispresent. The five (5) volts travels through the plug prong hot sidethrough the load and to the neutral which acts as ground to the circuit.The load has an associated resistive value which de-saturates acapacitor 58 of an RC circuit 56 (see FIG. 6). This de-saturation timeis calculated by using the symbol Tau where Tau is equal to theresistance multiplied by the capacitance. Using this simple equation,the RCTIME can be calculated and allowances of the resistance demand candetermine if the load is allowed to be presented with power. Referringto FIG. 5, a relay 60 is located below the receptacle 22 and is furtherdefined in FIG. 8. The relay 60 acts as a 5 volt and 120 volt selectorand provides a fail to low voltage solution. The NC aspect of the relayis always to the 5 volt circuit.

FIG. 6 shows a logical flow chart which determines the operationalstandards of the load requirements during the insertion of the loadsplug. The input hardware is defining only one element of the art andeach step of the logical diagram provides the solution for the loadsproperties at the time of load request.

FIG. 7 shows a schematic of a RCTIME circuit, defined by a resistor 62and the capacitor 56, whereby five (5) volts (702) is passed through acurrent limiter and junctions to a signal output to a fixed capacitorand out to a hot side brass connector 64 in the receptacle 22. The fivevolts pass through the load which acts as a resistor to ground (717).The signal of the RCTIME at the signal output depends on the resistanceof the load.

FIG. 8 shows a detailed schematic of the RC circuit 56 including adouble pole single throw relay 64 to distribute the voltage selectionand load activation signal both during the initial request and the RunTime Factor. An inductor 66 provides a current sense of the load duringrun time where the sensed current is converted to voltage through theprimary side of the T1 and is converted to direct current through aBridge Rectifier 68 and is furthered filtered via a capacitor 70 and isclamped to a 5 volt maximum signal by a diode 72 to prevent damage tothe I/O's on the microcontroller 40. The relay 64 is controlled viaDarlington or equivalent transistor or transistor packages.

FIG. 9 is a logical flow chart for the RFID or equivalent identificationmethods. The presence of the RFID can control the load request as wellas control the load time in which the load is operational. Theidentification methods of the load can allocate the time or conditionsin which the load is operational and allow programming of theidentification methods to define user or device dependence upon thereceptacle.

Various loads have characteristics which determine the time/current loaddemands whose inrush current is unique to each load. Each load has aspecific operational inductance quantity that measures theelectromagnetic induction of an electric circuit component; it is aproperty of the component itself rather than of the circuit as a whole.The self-inductance of a circuit component determines the magnitude ofthe electromagnetic force (EMF) induced in it as a result of a givenrate of change of the current through the component. Similarly, themutual inductance of two components, one in each of two separate butclosely located circuits, determines the EMF that each may induce in theother for a given current change.

The time required for the capacitor 58 to a predetermined percentagecharge of the battery voltage, 63.2%, after the switch is closed is theproduct of the resistance and capacitance T=(R*C). For example, a 100 uFcapacitor and 100K resistor would require 10 seconds to charge to 7.6volts using a 12 volt battery.

In one embodiment, the microcontroller 40 contains 16 I/O which utilize4 for the current sense and 4 for the inductance characteristic RCTIMEcalculations leaving 8 I/Os for expansion. Such expansions include butare not limited to RFID and near magnetic field modulation used byHewlett Packard Memory Spot chip.

FIG. 10 is an exploded view of the boards of an exemplary receptacle 22,according to an embodiment of the present invention. The top board 74 isthe receptacle plug base with brass receivers which contains a neutralside switch 32A under the left neutral side. This switch 32A detects thepresence of the plug 34 when inserted properly into the brass receiver52. This sends a 5 (five) volt signal to the board 76 which analyzes adrop in voltage through a capacitor where 63% of the capacitance drop isdetected and counted for comparison in a library contained in the firmware of the microcontroller's operational program. This is the maincomponent of the receptacle 22 and the other elements create a moresafety efficient design. Below is a brief explanation of each elementadding to the operation of the receptacle.

An RFID allows the receptacle 22 to utilize a card or pog (not shown) toobtain power from the receptacle which has both onboard firm wareprograms to allow different programmable operational parameters of theoutput power. Not only will it have power allotment but also time ofpower operation to a particular load. The user may define proper loadconfiguration and demand does not exceed the receptacle's currentcapacity by overriding the MCU's internal program for proper operation.

In one embodiment of the present invention, a thermometer or temperaturesensor 78 may be coupled to the load sensing circuit 18 for sensing anambient temperature. The load sensing circuit 18 compares the ambienttemperature with a predetermined acceptable temperature range andresponsively cuts off power to the output terminals if the ambienttemperature is outside of the predetermined acceptable temperaturerange.

In the illustrated embodiment, the thermometer 78 is embedded to thedesign in order to allow the user to define in the firm ware whatambient temperature is allowed for proper operation of the receptacle22. If the receptacle detects fire in the vicinity, it may be programmedto shut down out going power to the load to prevent electrical hazardconditions.

In another aspect of the present invention, a relative humidity sensor80 may be coupled to the load sensing circuit 18 for sensing therelative humidity of air around the apparatus. The load sensing circuit18 may compare the relative humidity with a predetermined acceptablehumidity range and responsively cut off power to the output terminals14, 14A, 14B if the relative humidity is outside of the predeterminedacceptable humidity range. The relative humidity sensor 80 detects thepresence of water or moisture in and around the vicinity of thereceptacle whereby the user may define in the firmware the allowablehumidity of the air in and around the receptacle and determine a controlpoint to remove power to the load. Each environment is different and canbe programmed independently to act in a different manner according tothe load demand and volatility of the ambient conditions.

The MCU 82 is a microcontroller unit which contains instructions thatmonitor the load resistive and capacitive characteristics as well as runthe sensor elements which drive the operational parameters of thereceptacle 22 according to the environmental conditions. The MCU 82 isthe brains of the receptacle 22 and various MCU designs can be utilizedhowever it is the RCTIME which is monitored that gives the receptaclethe unique capacity to operate with external programs which control theoutput to each load.

The USB slot 84 is a universal serial bus that allows a CPU tocommunicate to the receptacle 22 in order to program the receptacle'soperational parameter according to user definitions. Other devices maycommunicate to the MCU through the USB such as a Zwave module whichallows wireless communication of the receptacle to report to a centralmonitoring system or a web servlet can communicate through the web tothis device as well to make the receptacle networkable.

A Zwave Module is a wireless module which transmits and receives data atpreset data rates. This data can be utilized for various operationalsettings of the receptacle as well as monitoring the loadcharacteristics of current, voltage and frequency. Line conditions maycause low momentary sags or even high voltage spikes which can damagesystems connected to the receptacle. If such conditions go undetectedfor a prolonged period of time, damage to the load may be eminent. Theintelligent arcless receptacle can prevent such actions and allow theuser interface to make such events known through alerts given at themonitoring station wirelessly connected to the receptacle. APC (AmericanPower Conversion) is known for their legendary reliability throughintelligent power inverters which provide uninterruptible power toloads. Their output power is not monitored in any

FIG. 11 shows a down view of the top side of the brass receiver board74. On the neutral side of the board is a momentary switch 32A whichdetects the presence of the plug 34 when properly inserted in thereceptacle 22. Holes in the top and bottom of the board providemechanical support as well as electrical connection to the adjacentlower boards through pin standoffs.

FIG. 12 shows a RFID board 86 at the top of a middle board 88 whichallows the use of RFID cards or tags which provide operational solutionsfor overriding the output power by firmware or software userdefinitions. Below the RFID board 86 is a Relative Humidity andTemperature sensor board 90 which provides a threshold cutoff circuitwhen moisture and temperature levels are out of operational range of thereceptacle. The MCU board 76 is below the RFID and RelativeHumidity/Temperature boards 86,90 and provides the control portion ofthe circuit of the receptacle 22. The board 88 in FIG. 12 is the centerboard 88 which emanates a USB controller connection to the MCU whichcontrols the relays (bottom of board) via a Darlington transistor array.

FIG. 12 is a power supply with mechanical support pins located at thetop of the board which provides electrical connections to the middlecontroller board. A pin out to the USB board is provided for thecommunications to the receptacle. 120 volt AC power is converted to 12volt and 5 volt to provide power for the elements of the receptacle.

Sensors may be added to the design in order to expand on the valuablecapabilities of the related art “Shock Safe Receptacle”. Temperaturecontrollers can alter the voltage output to allow the user to define theoperational parameters of the receptacle to adhere to the necessity ofsafety and location of the said receptacle. A device may need to operatesafely less than 80 degrees and if the receptacle determines theenvironment exceeds the range of temperature required by the device tooperate safely it can turn off the power and alert the user of actionstaken which were set by said user cognoscente of the operationaltemperature requirements. Furthermore the added feature of RelativeHumidity assessment by the receptacle allows the user to further controlthe power distribution to meet or exceed the operational requirements ofsaid device. Further safety is given when the receptacle removes powerwhen conditions warrant such as fire or flooding or even child squirtingwater in the receptacle face thus preventing and eliminating a possibledeadly electrical shock to said child.

The added feature of RFID or Magnetic Field control allows the properoperation or timed operation of the receptacle. Places who have thisintelligent receptacle in place can offer use of the receptacle's powerfor specified time rates. Use of the RFID or Magnetic field allows thedevice to validate the proper device is plugged in to the receptacle andthe user guarantees the device to be safe or proper to the receptacleslocation.

The use of color sensors can allow scanning of color variation toreplace the RFID or Magnetic field for validation of device operation.

The aforementioned concepts utilize programming known to those skilledin the art of PIC programming and various Microprocessor languages suchas Standard C or Object Programming could be utilized to achieve thesame results and are understood to be elements of the related art. Theprogramming codes can utilize the RCTIME characteristics to determineload types and can prevent or allow said loads to operate with thereceptacle. This is known as SMA or Similarity Mapping Algorithms whichcan determine load characteristics associated with load origination.These intelligent receptacles can monitor the runtime to determine theoperational condition of the load to be within the limitations of saidloads capacity on the circuit which stems from the electrical panel andleads to each receptacle. The accumulation of the total load on theentire circuit is determined and communicated through wireless or wiredmeans.

Furthermore, this design accommodates a Senserion temperature andhumidity chip and it is understood that variations of this hardware maybe replaced with other similar components and like elements of the artmay be accomplished. The Senserion connects to one of the remaining I/Oports and code representing power control functions or actions due tothe Relative Humidity and Temperature regions prohibiting properoperation of the receptacle's power distribution elements.

Optical sensors such as color sensors or coded tag sensors can detectvariations which equate to operational parameters. A Color or coded Tagcan be scanned in front of the receptacle and allow operational runtimeor identify proper operation of the receptacle. Further enhancement ofthese tags replace the need for RFID or close Magnetic Field reading ifconsumer chooses this application.

The aforementioned concepts utilize programming known to those skilledin the art of PIC programming and various Microprocessor languages suchas Standard C or Object Programming could be utilized to achieve thesame results and are understood to be elements of the related art. Theprogramming codes can utilize the RCTIME characteristics to determineload types and can prevent or allow said loads to operate with thereceptacle. These intelligent receptacles can monitor the runtime todetermine the operational condition of the load to be within thelimitations of said loads capacity.

The design will validate the load to operate properly. The design willfurther validate the load condition once operating and canactivate/deactivate power to said load if conditions are programmed todo so. Furthermore the design can utilize a Data Bus, with said bus toinclude but not limit itself to Wireless, Power Line Carrier, Category 5Network, USB, Firewire, Serial or Parallel. Various other busses can beutilized to connect to the Microcontroller and allow programming offurther elements of related art to be applied.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made. Accordingly, otherimplementations are within the scope of the following descriptions.

A method of sensing the neutral and hot receivers for respectivelyreceiving the neutral contact and the hot contact of the plug, theneutral contact passing through the neutral receiver to the load andsupplying low volts to said load to determine RCTIME The method of wherethe neutral receiver senses low voltage through a low voltage detector.

The method where the low voltage detector can utilize a microcontroller,Microprocessor or other comparable circuits to achieve this method.

The method where the microcontroller utilizes firmware to calculate thevoltage loss due to load detection. The method where firmware actuate orsustains the contactor for output voltage. The method further comprisingof the firmware actuating a indicator indicating the proper currentdemand or improper current demand of the load. A method for sensing RFIDor equivalent magnetic or electromagnetic field modulations to determineproper accessibility to receptacle. A method further comprising offirmware in a microcontroller or microprocessor or other comparablecircuits to achieve this method which validates RFID or equivalentsignatures. A method where signatures are deemed acceptable orunacceptable load which respectively supply voltage and current toidentified load. A method for determining the RCTIME with amicrocontroller or microprocessor or other comparable circuits toachieve the method to validate load originality and accessibility ofoperation.

A method further comprising of programmable limitations of loads througha port or data bus where bus is USB, Serial or other comparable portssuch as wireless or Firewire.

A method for controlling the Time of power of receptacle aftervalidation of load is established. A method of monitoring the loadoperational parameters. A Method further comprising of load controlassociated with load condition whereby load condition determines powerallotment.

What needs to be pointed out is the need to not only detect an arc butto eliminate the possibility of an arc before it happens. Other elementsof the design are inherent to allow the use of technology to expand onthe functionality of the receptacle. Before the plug is inserted to thereceptacle there is no voltage present at the brass contactors therebyreducing the possibility of a shock to anyone who might insert a metalobject into the receptacle. Once the brass contactors are engaged, thereis a switch on the neutral side which evokes a 5 (five) volt DC signalthrough the load to ground to complete a circuit. The five volts passesthrough a fixed capacitor and out the hot side of the receptacle throughthe load and to ground. The load has a resistive nature which creates aRC network that gives you the value of Tau where Tau=RC. If the valuemeets the required limitations the five volts converts to 120 volts ACand gives the load the required operational voltage. It does not quitthere because there could have been a soft start circuit in place beforethe voltage demand thereby giving a false reading to the RC network andfooling the MCU allowance library. So a load monitoring system is put inplace which monitors the inrush current and Runtime Factor (RTF) tomaintain safety of the receptacle. If by chance the RTF exceeds theoperational limitations of the receptacle, a special circuit designed tomonitor, control and limit the output power to the load thus preventinga possible hazardous condition. The intelligence of the receptacle isrun by a standard MCU (Micro Controller Unit) which has programming tothe I/O pins which connect to various circuits responsible for loadmonitoring and control. These control options can be controlled bysoftware which alters the firm wares interaction with various loadsthereby creating a safer receptacle design.

There have been new designs which utilize a comparator circuit forresistance characteristics but these new designs do not take into mindthat the load demands have capacitance characteristics as well asresistive characteristics and the resistance measured by the comparatormay not represent the load's actual resistive characteristics. A relaywhich provides a switch circuit has a coil with a resistance of lessthan 8 ohms however the load itself could have a resistive value of lessthan an ohm. A direct short to ground could result in a fire if the loaddemand exceeds the receptacle's current capacity. Our new circuit designtakes this into mind while measuring the initial load resistivecharacteristic, it also has a soft start circuit monitor for runtimefactor.

The present invention provides a low cost solution for arc safety and areduction in risk of electrical shock. The intelligent receptacleutilizes intelligent chip ware to measure the resistance of the loaddemand and determines if inrush Watts is greater than the specifiedcurrent rating before energizing the hot side of the receptacle.Electrical receptacle outlets in walls and floors may present shock andelectrical fire hazards to consumers.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation.Obviously, many modifications and variations of the present inventionare possible in light of the above teachings, and the invention may bepracticed otherwise than as specifically described.

1. An apparatus for supplying AC Power to a load, comprising: a pair ofoutput terminals; a primary circuit electrically coupled to a source ofAC power and to the output terminals for selectively providing power ata low voltage at the output terminals or electronically coupling thesource of AC power directly to the output terminals, the primary circuitfor providing power at the low voltage at the application of the load;and, a load sensing circuit coupled to the primary circuit and thesource of AC power for determining a resistance associated with the loadat initial application of the load and controlling the primary circuitto electronically couple the source of AC power directly to the outputterminals if a proper load is detected.
 2. An apparatus, as set forth inclaim 1, wherein the load sensing circuit continues to supply power atthe low voltage at least during initial load characteristics associatedwith the application of the load.
 3. An apparatus, as set forth in claim1, the primary circuit including a switch coupled between the source ofAC power and the output terminals and having a first position wherepower at the low voltage is provided at the output terminals and asecond position where the source of AC power is electrically coupleddirectly to load, the load sensing circuit including a microcontrollercoupled to the primary circuit, the microcontroller for monitoring avalue of the low voltage during initial application of the load andcontrolling the switch in response thereto.
 4. An apparatus, as setforth in claim 1, including a second pair of output terminals and asecond primary circuit, the second primary circuit being electricallycoupled to the source of AC power and to the second pair of outputterminals for selectively providing power at a low voltage at the secondpair of output terminals or electronically coupling the source of ACpower directly to the second pair of output terminals, the secondprimary circuit for normally providing power at the low voltage at thesecond pair of output terminals when no load is connected to the secondpair of output terminals, wherein the load sensing circuit is coupled tothe second primary circuit power supply for determining a resistanceassociated with a second load at the second pair of output terminals atinitial application of the second load and controlling the secondprimary circuit to electronically couple the source of AC power directlyto the second pair of output terminals if a proper load is detected atthe second pair of output terminals.
 5. An apparatus, as set forth inclaim 1, wherein the apparatus is embodied in an electrical receptacle,the output terminals being electrically coupled to respective femaleopenings for receiving a respective prong of a plug of the load.
 6. Anapparatus, as set forth in claim 5, wherein the primary circuit includesa sensor coupled to the load sensing circuit for detecting the presenceor insertion of a prong into one of the female openings.
 7. Anapparatus, as set forth in claim 1, further including an audio and/orvisual indicator coupled to the load sensing circuit for providing anindication of a proper or improper load.
 8. An apparatus, as set forthin claim 1, wherein the load sensing circuit includes a capacitorelectrically coupled to the output terminals, the capacitor beingcharged to an initial predetermined voltage, the load sensing circuit indetermining the resistance of the load, senses the time for thecapacitor to discharge to a second predetermined voltage level afterinitial application of the load.
 9. An apparatus, as set forth in claim8, wherein the second predetermined voltage level is approximately 64%of the initial predetermined voltage.
 10. An apparatus, as set forth inclaim 1, the primary circuit including a load detection sensor and aswitch coupled to the sensor and the output terminals and having a firstposition and a second position, the switch being in the first positionwhen no load is present, wherein no power is supplied to the outputterminals, and in the second position when a load is present, the switchfor detecting application of the load and switching the switch from thefirst position to the second position.
 11. An apparatus, as set forth inclaim 10, wherein the apparatus is embodied in an electrical receptacle,the output terminals being electrically coupled to respective femaleopenings for receiving a respective prong of a plug of the load, whereinthe sensor is a mechanical switch for detecting the presence orinsertion of a prong into one of the female openings.
 12. An apparatus,as set forth in claim 1, the load sensing circuit for determining aresistance associated with the load after initial application of theload, if a proper load is not previously detected and confirming thatthe load is not proper as a function of the resistance associated withthe load after initial application of the load.
 13. An apparatus, as setforth in claim 1, further including a thermometer coupled to the loadsensing circuit for sensing an ambient temperature, the load sensingcircuit for comparing the ambient temperature with a predeterminedacceptable temperature range and responsively cutting off power to theoutput terminals if the ambient temperature is outside of thepredetermined acceptable temperature range.
 14. An apparatus, as setforth in claim 1, including a relative humidity sensor coupled to theload sensing circuit for sensing the relative humidity of air around theapparatus, the load sensing circuit for comparing the relative humiditywith a predetermined acceptable humidity range and responsively cuttingoff power to the output terminals if the relative humidity is outside ofthe predetermined acceptable humidity range.
 15. An apparatus, as setforth in claim 1, further including a controller for reading a controldevice and responsively overriding operation of the load sensingcircuit.
 16. An apparatus, as set forth in claim 1, wherein the loadsensing circuit includes a microcontroller.
 17. An apparatus forsupplying AC power to a load, comprising: a primary circuit electricallycoupled to a source of AC power, the source of AC power having a neutralterminal and a positive terminal, the primary circuit including: a powersupply and voltage regulator circuit being electrically coupled to theneutral and positive terminals and supplying power at a low voltage; afirst switch coupled to the power supply and voltage regulator circuit,for sensing application of a load and responsively electrically couplingthe power supply and voltage regulator circuit to the load; a secondswitch electrically coupled between the first switch and the load andhaving a first position where the first switch and the load areelectrically coupled and a second position where the source of AC poweris electrically coupled directly to load; and, a load sensing circuitcoupled to the power supply and voltage regulator circuit fordetermining a resistance of the load after application of the load andcontrolling the switch to move to the second position if a proper loadis detected.
 18. An apparatus, as set forth in claim 17, the loadsensing circuit for determining a resistance associated with the loadafter initial application of the load, if a proper load is notpreviously detected and confirming that the load is not proper as afunction of the resistance associated with the load after initialapplication of the load.
 19. An apparatus, as set forth in claim 17,wherein the load sensing circuit includes a microcontroller.
 20. Areceptacle for supplying AC power to a load, the load having anassociated electrical plug, the receptacle comprising: a set of outletterminals; an outlet for receiving the electrical plug associated withthe load, the outlet having at least two associated electricalconnectors electrically coupled to the outlet terminals for providingelectrical connection to associated prongs of the electrical plug; aprimary circuit electrically coupled to a source of AC power and to theoutput terminals, the source of AC power having a neutral terminal and apositive terminal, the primary circuit including: a power supply andvoltage regulator circuit being electrically coupled to the neutral andpositive terminals and supplying power at a low voltage; a first switchcoupled to the power supply and voltage regulator circuit, for sensinginsertion of the electrical plug into the outlet and responsivelyelectrically coupling the power supply and voltage regulator circuit tothe load; a second switch electrically coupled between the first switchand the output terminals and having a first position where the firstswitch and the output terminals are electrically coupled and a secondposition where the source of AC power is electrically coupled directlyto the output terminals; and, a load sensing circuit coupled to thepower supply and voltage regulator circuit for determining a resistanceof the load after insertion of the electrical plug into the outlet andcontrolling the switch to move to the second position if a proper loadis detected.